Intravital imaging of orthotopic and ectopic bone

Bone homeostasis is dynamically regulated by a balance between bone resorption by osteoclasts and bone formation by osteoblasts. Visualizing and evaluating the dynamics of bone cells in vivo remain difficult using conventional technologies, including histomorphometry and imaging analysis. Over the past two decades, multiphoton microscopy, which can penetrate thick specimens, has been utilized in the field of biological imaging. Using this innovative technique, the in vivo dynamic motion of bone metabolism-related cells and their interactions has been revealed. In this review, we summarize previous approaches used for bone imaging and provide an overview of current bone tissue imaging methods using multiphoton excitation microscopy.